Just because: Narrow Hood GP35

[chessie system fan]

Many, many moons ago, Athearn had the most easily available diesels in HO, but they made their hoods too fat (I'm guessing because of the motor technology then).  I've got a lot of old magazines and I've come across several articles about making them scale width.  Back when Athearn was the only option for some kinds of units that's what you had to do.

N scale has a good number of EMD locomotives that are not scale width either.  Atlas' GP30 and GP35, and all Kato EMD locomotives (I think).  Maybe more.  Like Athearn back then, these are the only models available of these EMD units.

 I had some spare shells so I decided to make a narrow, scale width GP35.  I basically copied those old HO articles, and it's actually easier in N scale because the walkway is a separate piece.

To begin, I sawed the shell in half.  The particular saw I used cut away the exact amount needed (~0.025"-0.30"). 

The front and back have to be completely new since the wide hood causes the end angles to be too wide.  The front has a very convenient seam right behind the cab, while for the back I filed to the edge of the grills.  The new front is from a GP40, while the new rear is from a GP38-2.  An SD35 would have  been a slightly better starting point, but I didn't want to risk my spare shell on the project. 

I then cemented the two halves together, along with the new front and back.





This is what I have so far.  I've added a little body putty to the middle seam, but it needs more.  The shell needs new fans and exhaust, obviously, and that's the next step.  This is my first major kitbash, so there's lots of little things I would do differently.  The next one will be much better.

So, why go to all this trouble?  First, because it's possible and I've never seen anyone do it before.  Second, though the difference is small, it is perceptible.  I think this is more true of the GP30 and GP35 because they are short.  Longer Kato SD units fare much better visually.  To my eye, the difference is most striking around the GP35's inertial filter hatch, perhaps because it's flat.



The bigger third reason is that this is a warmup for a GP30 project, if I ever get around to it.  The extra width is very noticeable around the cab.  Just look at this image:

http://rrpicturearchives.net/showPicture.aspx?id=2985980

Compared to the sleek and edgy styling of the prototype, the Atlas model looks a bit pudgy.



Things still to do: more body putty, new fans, walkway modifications, and narrowing the mechanism.

[Kisatchie]

I had some spare shells so I decided to make a narrow, scale width GP35....
To begin, I sawed the shell in half...

Hmm... ohhhh, you cut
it in half LENGHTHWISE...

[Mark5]

I hate those Kato (and the Atlas/Kato) fat hoods too, but you are braver than I am!

Can't wait to see the final result.

(For the record, I have a bunch of the Kato and Atlas/Kato (GP30, GP35) fat hoods, and fixing the numberboards on the long hood is ambitious for me lol).

Mark

[chessie system fan]

I've removed most of the fans and the turbocharger.  In hindsight, I should have done this before I assembled the shell as it's quite fragile.

I've also started work on the mechanism.  The shaded part needs milling.



I'm guessing a potential problem will be the motor.  These have larger flywheels that might be too large now.  I suppose the solution will be to use the motor with the smaller flywheels and hope it fits the GP35 motor saddle.  If that doesn't work, I guess I'll need to swap flywheels.

We shall see.

[Sokramiketes]

Max would just run a mill file on the spinning flywheels until they were the right diameter...

Cool project!  I hope you don't get to the GP30 project so that I can still live with mine.  Hopefully we're getting far enough away from the original tooling that it starts making sense for a fresh GP30/35 series.

[daniel_leavitt2000]

I'm not holding out hope for a new scale model. Atlas did retool the GP30 for phase1 (I think) only a few years ago. So they obviously think these are good enough. Then once we start down that road... SD40, SD45, U30, C30, ugh I don't want to think about it.

[Ed Kapuscinski]

Instead of milling the mech, have you tried one from a LL GP20? I think they fit, and then it might only be a fuel tank swap.

[chessie system fan]

Still working on the fans, so nothing photo-worthy yet.  I've also acquired a spare GP30 shell.  Studying that more closely makes me very glad I started on a GP35 first.  It's several magnitudes more difficult.

I'm pretty sure a GP20 has the same truck centers as a GP9, which is a tad too short, but I'll double check.  Good thinking.

[Ed Kapuscinski]

I know, in the past, I put one under a GP35 shell. I remember it looking "ok", but I definitely just eyeballed it and didn't measure it, so it very well may be off.

[Mark5]

GP7, GP9, GP18, GP20 = 31' boltster centers
GP30, GP35 = 32' between boltster centers

[chessie system fan]

I finally have an update!

The shell is far too fragile to work on by itself. It's broken a few times at the rear.  I needed to do the mechanism first to use it as support.  After quite a while with my motor tool I quickly realized that this was a very inefficient use of my time.  Finally, I've been able to use a friend's bench grinder.  But even that didn't get as much metal as I wanted. 

Much more milling later and this is the result:




That's an old LL GP20 motor temporarily in there.  Fits perfectly.

Now I can get back to the shell. 

[peteski]

That motor is a dead-ringer for Atlas motors (the way the pickup strip is attached to the motor body).

[cjm413]

I finally have an update!

The shell is far too fragile to work on by itself. It's broken a few times at the rear.  I needed to do the mechanism first to use it as support.  After quite a while with my motor tool I quickly realized that this was a very inefficient use of my time.  Finally, I've been able to use a friend's bench grinder.  But even that didn't get as much metal as I wanted. 

Much more milling later and this is the result:




That's an old LL GP20 motor temporarily in there.  Fits perfectly.

Now I can get back to the shell.

Would a Phase IIb GP35 be an easier option?



This would allow more use of the GP38/40 (e.g. clean air room with raised dust bin hatch), also most of the radiator section from the Atlas SD35.   The GP35 would still provide the (narrowed) engine room section and the doors below the SD35 radiator grills.

[chessie system fan]

I've actually considered doing just that.  I just haven't bought the extra parts yet.  That's one reason why I haven't worked on this project more.  The current shell is extremely fragile.